table lamp-replacment mains cable

[600rob]

Hi

Ive got another electrical question.

Ive got a table lamp that’s not working, basically its a small lamp with 3 20 watt lamps and is connected to the mains via a 2 core cable (live & neutral) with a 13a fused socket and an in line switch to operate the lamp.

The reason its not working is because the switch internals have been damaged and thus it is not working properly.

Ive got something which i think i may be able to use as a replacement.
It’s a 3 core length of cable with a 3 amp fused plug and an inline switch.

I was wondering if i can do the following safely to use it as a replacement part

1: blank off/cover the earth cable with insulating cable and only connect the live and neutral to the lamp.
2. replace the 3 amp fuse with a 13 amp

If i carry out the two points above will the lamp still be safe to use?

Many thanks

rob

 

[stem]

Would it not be easier just to swap the in line switch over?

3 x 20w = 60w so you should only have a 3A fuse in the plug anyway. A 3A fuse is capable of handling a 690w load. More than enough for your lamp.

 

[600rob]

both swiches are those sealed units types so id have to cut wires/tape them up etc. plus id have an unused earth from the new switch.

if possible would rather just wire it into the lamp direct and tuck the unused earth neatly inside the body of the light out of sight.

I thought the same thing about the fuse but wasnt 100% sure. Thanks for confirming that.

 

[ban-all-sheds]

And probably more than the cable can carry, so it should have been replaced anyway.

 

[600rob]

And probably more than the cable can carry, so it should have been replaced anyway.

Off topic, but after reading this on the net the other day i had a look around my flat and there are quite a few appliances that are under 700w but all came fitted with 13 amp fuses
why do maufacturers do this?

 

[stem]

Often they draw a higher current when they start up, usually motor driven items, in particular fridges and freezers that start up under load. Once they're running they draw less current, but the fuse has to cope with the initial 'rush'

Other items have lower rated internal fuses. I remember my parents invested in a 'teasmade' It had a 13A fuse because of the power required by the kettle, but most of the time only the clock motor was running at probably 2W, so a smaller internal fuse was fitted just to protect that.

 

[GaryMo]

Off topic, but after reading this on the net the other day i had a look around my flat and there are quite a few appliances that are under 700w but all came fitted with 13 amp fuses
why do maufacturers do this?

Because the fuse in the plug top is in place to protect the flex, not the appliance. It all depends on the size of the flex supplying the appliance.

 

[600rob]

Ahh i see thanks for the info.

Im my case the flex is 0.75mmm sq.

Anyway going back to my original post, does anyone know if i can use the 3 core flex with inline switch to replace the original flex which is 2 core?
(i would just connect the live and neutral, and omit/blank off the earth)

 

[ban-all-sheds]

Ahh i see thanks for the info.

//www.diynot.com/forums/viewtopic.php?p=81696#81696

Im my case the flex is 0.75mmm sq.

Maximum fuse 6A.

Anyway going back to my original post, does anyone know if i can use the 3 core flex with inline switch to replace the original flex which is 2 core?

Yup.

(i would just connect the live and neutral, and omit/blank off the earth)

Connect it to the earth terminals in the plug and the switch. At the lamp end try to find room inside for a piece of choc-block rather than just cutting it off.

 

[LoveRocket]

Anyway going back to my original post, does anyone know if i can use the 3 core flex with inline switch to replace the original flex which is 2 core?
(i would just connect the live and neutral, and omit/blank off the earth)

Yes, that's fine.

 

[ban-all-sheds]

Connect it to the earth terminals in the plug and the switch. At the lamp end try to find room inside for a piece of choc-block rather than just cutting it off.

 

[stem]

Because the fuse in the plug top is in place to protect the flex, not the appliance.

Er.. not quite true. If that was the case you could get a 8W lamp and connect it to 2.5mm flex, put a 13A fuse in the plug and say that it will be nice and safe.

The flex and the fuse are both sized according to the appliance. That is why heavy loads such kettles toasters and washing machines for example have thicker flex than lamps, radios and shavers.

 

[GaryMo]

It's very much true and the reason toasters etc have 'thicker' flex is because they draw more current.
It's not economical to use 1.5mm flex for a table lamp when you're making tens of thousands.

 

[stem]

toasters etc have 'thicker' flex is because they draw more current.

I know, that's what I just said.

that is why heavy loads such kettles toasters and washing machines for example have thicker flex

 

[GaryMo]

Er.. not quite true. If that was the case you could get a 8W lamp and connect it to 2.5mm flex, put a 13A fuse in the plug and say that it will be nice and safe.

OK then, tell me why your example above is unsafe apart from the fact that it'll be more difficult to terminate a 2.5mm2 flex in a plug top.